In general, the invention relates to a force generator for generating a force to be applied to a structure with the aid of an inertial mass and a drive circuit for this purpose. The force generator serves in particular to control vibrations in structures. For example, targeted counter vibrations are to be introduced into a structure in order to reduce the overall level of vibrations in the structure. Such force generators are used, for example, in a device for vibration control. The invention is used in particular in vibration control in helicopters and aircraft.
Force generators serve to generate a desired force by means of a predetermined inertial mass. In the process, the force results from the inertia of the inertial mass which is moved in any way. In order to generate as great a force as possible, the inertial mass can, on the one hand, be moved at as fast an acceleration as possible or with a great displacement. Alternatively, or in addition to this, such a great force can also be generated by as great an inertial mass as possible.
Force generators are, for example, used for the targeted introduction of forces into vibrating structures such as aircraft, motor vehicles or machine components in order, for example, to counteract vibration levels and eliminate them. Force generators for vibration damping are also known as inertial mass actuators. They are attached, for example, as additional systems to existing machines or devices in order to reduce vibrations or to introduce process forces. Force generators or inertial mass actuators are constructed, for example, from a spring-inertial-mass system into which an actuator is integrated. Piezoelectric actuators are used, for example, in the process.
Examples of force generators for introducing vibrational forces of the type stated in the preamble of claim 1 are known from WO 2007/073820 A1 and US 2005/0280332 A1.
In WO 2007/073820 A1 in the process, an inertial mass is provided on a flexural arm, which is caused to vibrate flexurally by means of one or more piezoelectric actuators. For this purpose a drive in the form of an electronic drive circuit for driving the actuator or actuators is provided.
Examples of electronic drive circuits for driving piezoelectric actuators of force generators are described and shown in EP 0 907 036 A2, US 2005/0280332 A1, US 2005/0285477 A1, US 6 411 009 B2, US 2008/031667 A1 and EP 2 733 839 A1.
In piezoelectric force generators an amplifier is provided for constructing the electronic drive circuit.
In comparison with electrodynamic systems, known piezoelectric force generators are disadvantageous in that the weight of the required amplifier is higher due to the principle. The reason for this is, in particular, an inductor which is used in clocked amplifiers for smoothing the output voltage.